Electric manipulations of hydrogel on a digital microfluidic platform

For the first time, we demonstrate the electric manipulations of (1) crosslinkable polymer solution droplets by electrowetting and dielectrophoresis, (2) crosslinked polymer and hydrogel blocks by dielectrophoresis, and (3) pre-polymer solution and crosslinked hydrogel containing cells. Different hydrogel blocks cured from individually-driven pre-polymer droplets provide 3D microenvironments for in vitro cell culture. With the ability to actively drive the pre-polymer droplets, assemble the hydrogel blocks, and arrange the cells inside the hydrogel, this work provides an essential approach to tissue engineering, cell-cell interaction, stem cell differentiation studies on a highly programmable digital microfluidic device.